add support for md front matter & open page unlisted

- support page config define in front matter
  - support `title`, which can set HTML title.
    - if `title` is not set, then HTML title will try find page title defined in book.xml
	- if `title` is set but <h1> title not set, it will generated a <h1> title using the value of `title`
  - support `configurations` which can set page level configs here.
- now can open page that has .md file but not defined in book.xml (must in a book defined)
- old.title.gen is not supported yet.

book.xml

@@ -12,8 +12,28 @@
 	<book_name>ph-Bookshelf Wiki</book_name>
 	
 	<contents>
+		
 		<Page id="ph-bookshelf">the ph-Bookshelf</Page>
 		<Page id="web-server">Web 服务器配置</Page>
+		<Chapter>
+			<caption>高级选项</caption>
+			<Page id="enhanced/robots-policy">robots.txt</Page>
+		</Chapter>
+		
+		<Separator />
+		
+		<!-- <Chapter root="olds/">
+			<caption>旧书</caption>
+			<Page id="main">ph-Bookshelf</Page>
+			<Page id="install">安装使用</Page>
+			<Chapter>
+				<caption>Datas 书写</caption>
+				<Page id="data-write/bookshelf">建立书架</Page>
+			</Chapter>
+			<Page id="custom">自定义网页样式</Page>
+			<Page id="plans">开发计划</Page>
+		</Chapter> -->
+		
 	</contents>
 	
 </Book>

web-server.md

@@ -1,6 +1,6 @@
 ---
 configurations:
-- highlightjs.languages: "apache"
+  highlightjs.languages: "apache"
 ---
 
 # Web Server